Abstract Early life adversities, including childhood abuse, neglect, and material hardship, affect one in three American women and are associated with an almost 40% increased risk of adult obesity. However, little is known about how these exposures influence pregnancy weight outcomes that have important public health consequences, such as excess pregnancy weight gain, postpartum weight, and infant birth weight. This knowledge gap is important because these pregnancy weight outcomes have major impacts on future obesity risk for women and their children. In preliminary work leading to this study, we found that early life adversities were associated with a 50% increased risk of excess pregnancy weight gain overall, and an 80% increased risk among women of normal pre-pregnancy weight. These findings suggest that women with early adversities should be offered interventions to improve pregnancy weight outcomes, as these could reduce subsequent obesity for both themselves and their children. However, there is currently limited research on early life adversities and pregnancy weight outcomes, which means that the mechanisms contributing to unhealthy pregnancy weight, which could inform intervention, are unknown. Our preliminary work has identified a potential set of factors that might be targeted by intervention to improve pregnancy weight outcomes: modifiable young adult risk factors such as binge eating and unhealthy weight control behaviors. These risk factors are common among women with early adversities and appear to predict excess pregnancy weight gain. We propose to conduct rigorous research building on this work, to investigate the relationships between early life adversities, young adult risk factors, and pregnancy weight outcomes. To conduct this research, we will overcome a barrier to prior studies of pregnancy weight outcomes, which is that existing datasets with pregnancy weight information have little information about women's pre-pregnancy lives. In the proposed project, we will create an innovative new cohort by linking pregnancy data from surveys and medical records with existing longitudinal information on ~520 women participating since adolescence in a 15-year study of weight-related health. This unique dataset will enable investigation of: (1) how early adversities experienced by women are associated with their pregnancy weight outcomes; (2) how early adversities are associated with young adult risk factors, and how young adult risk factors are associated with pregnancy weight outcomes; and (3) the extent to which associations between early life adversities and pregnancy weight outcomes are mediated by young adult weight-related risk factors. The proposed project answers the call of the Institute of Medicine and other experts for insight into life-course risk factors for maternal weight problems that can inform interventions across the lifespan.